Q61 of 66 Page 15

A box contains 20 cards numbered from 1 to 20. A card is drawn at random from the box. Find the probability that the number on the drawn card is

(i) divisible by 2 or 3,


(ii) a prime number.[CBSE 2015]

(i) Numbers divisible by 2 or 3 from 1 to 20 are 2,3, 4, 6, 8,9, 10, 12, 14,15, 16, 18, 20

So, Favourable number of outcomes = 13


Total outcomes = 20



(ii) Prime numbers from 1 to 20 are 2, 3, 5, 7, 11, 13, 17, 19


So, Favourable outcomes = 8


Total outcomes = 20


More from this chapter

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59

Two different dice are thrown together. Find the probability that the numbers obtained

(i) have a sum less than 7


(ii) have a product less than 16


(iii) is a doublet of odd numbers. [CBSE 2017]

 60

A bag contains 15 white and some black balls. If the probability of drawing a black ball from the bag is thrice that of drawing a white ball, find the number of black balls in the bag.[CBSE 2017]

 62

A card is drawn at random from a well - shuffled deck of playing cards. Find the probability that the card drawn is

(i) a card of spade or an ace


(ii) a black king


(iii) neither a jack nor a king


(iv) either a king a queen [CBSE 2015]

 63

A game of chance consists of spinning an arrow on a circular board, divided into 8 equal parts, which comes to rest pointing at one of the numbers 1, 2, 3, …, 8 (Fig. 9), which are equally likely outcomes. What is the probability that the arrow will point at (i) an odd number (ii) a number greater than 3 (iii) a number less than 9.

 [CBSE 2016]